Hot-wire clamp



y 23, 1950 H. w. BODENDIECK 2,509,083

HOT-WIRE CLAMP Filed May 24, 1948 s Sheets-Sheet 1 f i y May 23, 1950 H. w. BODENDIECK HOT-WIRE CLAMP w M 4 W10.

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May 23, 1950 H. w. BODENDIECK 2,509,083

HOT-WIRE CLAMP Filed May 24, 1948 3 Sheets-Sheet 3 v fiy/enior I fiel ygfiodendzeck Patented May 23, 1950 UN IT ED STATES PAT F F'ICE;

HOT-WIRE CLAMP Henry W. Bodendieck, TQYIOIVHIG, Ill.

Application'May24, 1948, Serial-No; 28,906-

Claims.

The present invention relatestohot wire clamps, and is particularly concerned with electrical connectors ofthetypeadapted to be used in connecting transformer leads, jumper leads, or any other connectionswhich may be made to a transmission line or from. one line to another, on lines which may be energized or d'eenerg'ized;

The present application is a: continuation in part of my prior application, Serial. N0. 636,655, filed December 21, 1945, for Hot wire clamps.

One of the objectsofthe invention is the provision of an improved electricalconnect'or of the clamp type which is springactuatedin one direction and which isadaptedto be actuated in the other direction by meansof'a cam, in such manner that it is unnecessary. to utilize any" threaded parts.

The. ordinary spring type clamps of the prior arthave been unsatisfactory,and,- therefore, they have been for the most part superseded by connector clamps utilizingthreaded members for opening and closing the jaws of a connector upon an electrical wire. These'thread'ed members were necessary to secure sufficient pressure and to maintain the pressure on an electric wire to: re ducethe contact resistance and carry thecurrent load which is'impo'sed upon such connectors.

Where screw type clamps'are used, experience" has proven that these clampsare unsatisfactory,

particularly where they are used in service out of doors near the coastlines; where the atmosphere contains salt; or in the neighborhood of industrial: establishments; where'the atmosphere contains' acid fumes. Both of" these atmospheric conditions result in corrosion within the cut threads, and in a short time this makes the threaded portions inoperabl'e and unfit to 'per form all of the uses intended for the clamp.

In other locations where vibration'is excessive upon the conductor to which the connector is'applied; the threaded screw vibrates loose, causing a loose connection and damage to the electrical conductor, which'may'cause serious delays andbreakdown of transmission'lines; and thelike.

The spring type clamps of the-prior art with became: very diflicultf and.insrnostcases impossiblethe spring clamps of the prior art open in this manner by pushing, them against the line.

One of the objects of the present invention is the provision of an improved" type of clampor' connector which permits" the operator" to install the clamp-upon a conductor, either energized or deenergized, safely andeasily, and which eliminates any possibility of the clamp loosening on the linethroughvihration or any possibility of the freezing ofthe clamp by. corrosion of threads caused by atmospheric conditions.

Another object of theinvention is the provision" of an improved operating-means for clamping connectors of the type described which" is not" subject to any of the disadvantages of threaded operators,- and which willopen or close the jaws under high resilient pressure without imposing any substantial strains upon the transmission line.

Another object of-the invention isthe provision of any. improved hot Wire. clamp, which may be provided withany of a plurality of different operating: members; such as an operating member permanently attached to an insulating pole; an operating member having ahandle-to bemanipulated-withthe handswearinggloves;.an operating.

member having an eye of the type gripped by clamp sticks, oran operating-member: having aslottedfiange tobe ad-justably-secured to the secaled Universal? pole.-

Another object of theinventionis the provision of an improved clam-p of the class described" which hasa three point pressure contactuponthe conductor, and which I will accommodate various sizes of wires, the three point contact jaws providing more contactarea andbetter rigidity on the? conductor,- andavcidingrmarringof the-lines= or the possibility of any undue n'lovement either endwise or up or down; thus adding material-lyto the life of the conductor and =to the satisfactory operation 1 of the clamp.

Another nbject of the-invention-is the provision-- of an improved spring pressed hot: wireclamp, which is provided with a cam actuator foropening andclosingthe clamp; in whichprovision is madetoprevent the rattling orvibration oithe actuator withrespect-to thehot-wire clampi after:

th clam-p engaging. ahli neconductor and pres:- sure has.- been a! removed from the cam by such engagement so that there will be no danger of static due to such rattling.

Another object of the invention is the provision of a plurality of different forms of hot wire clamps of the class described, which are sturdy, simple, capable of economical manufacture, and adapted to be used under the most adverse conditions without possibility of corrosion affecting their operating characteristics or freezing them on the line, or any possibility of their becoming loose inadvertently.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the three sheets of drawings accompanying this specification,

Fig. l is a fragmentary side elevational view of a hot wire clamp embodying the invention shown in connection with a clamp stick, the clamp being in closed position;

Fig. 2 is a rear elevational view of the same clamp without the clamp stick;

Fig. 3 is a sectional view taken on the plane of the line 33 of Figure 2, looking in the direction of the arrows;

Fig. i is a side elevational view in partial section on a plane which passes through the axis of the operating member with the clamp in the open position;

Fig. 5 is a fragmentary sectional view taken on the plane of the line 5-5 of Figure 4, looking in the direction of the arrows and showing the position of the parts at the time of assembly;

Fig. 6 is a view similar to Figure 4 of a modification in which the operating member is freely removable from the hot wire clamp when it has been clamped on the line;

Fig. 7 is a view in perspective of an operating member for a hot wire clamp of the class described, which operating member is removable from the clamp as a unit and which is provided with an eye structure of the type adapted to be received in a clamp stick;

Fig. 8 is a fragmentary view in perspective of the lower portion of another form of operating member intended to be actuated with the hand, using gloves if the line is energized with a low voltage;

Fig. 9 is a fragmentary view in perspective of the lower part of another operating member of a type permanently secured to the end of an elongated wooden insulating pole;

Fig. 10 is a fragmentary view in perspective of the lower end of another modified form of operating member, which is adapted to be removably secured to the upper end of an insulating pole of the Universal type, which is equipped with a flange and a clamping bolt on its upper end;

Fig. 11 is a view similar to Figure 5, showing the arrangement of these parts for a removable operator of the type of Figure 6; and

Fig. 12 is a view in perspective of the operator member of Figure 6.

Referring to Figures 1 to 6, these are views of a hot wire clamp, which is provided with an operating member equipped at its lower end with an eye structure of the same size as is usually employed upon the ordinary hot wire clamps of the prior art. The size of such eye structures is standard so that they may all be engaged by the Various clamp sticks made by diiferent manufacturers. I desire it to be understood, however, that the present hot wire clamp may be provided with any of the operating members which are shown in Figures 7 to 10, and which differ mainly in the shape of the lower end of the operating member.

For example, the operating member 20 of Figure '7 has its shank 2| provided with a standard eye 22, of such a size as can be engaged by an ordinary clamp stick.

The same operating member might be equipped with the formation shown in Figure 8, in which the shank 24a is provided with an integral transverse cylindrical bar or handle 23, preferably having ball-shaped formations 2 at each end. Such an operating member as shown in Figure 8 may be actuated by direct engagement with the hand when not energized, but when it is applied to energized conductors, preferably of low voltage, the lineman should wear a rubber glove, and this type of operator should never be employed for high voltage lines.

Referring to Figure 9, in this case the shank Zlb is integrally attached to the end Wall 25 of a metal ferrule 28. The metal ferrule 26 has a cylindrical body 21, with a cylindrical bore 28 fitting on the end of an elongated insulated pole 29, to which it is permanently attached by a transverse pin 38. The pin 30 passes through the ferrule and the pole and is riveted over at both ends.

Referring to Figure 10, this is another modified structure for the lower end of the operating member, of the type adapted to be attached to the socalled Universal pole. In this case the shank 2 to has a flattened disc-like portion 3!, which is provided on one side with a plurality of radial teeth 32.

A slot 33, having a circular base 34', extends inwardly from the end of this operating member for passing a screw bolt on the Universal pole. As is well known, the Universal pole has its upper end provided with a circular flange into which a screw bolt is threaded, and the flange iii of the operator of Figure 10 may have the screw bolt located in the slot 33 and may be clamped to the Universal pole in any one of a multiplicity of different angular positions. Of course the axial position is the proper one when an operator is to be rotated by means of the pole.

Referring now again to the devices of Figures 1 to 6, the lower end of the operating member used in these hot wire clampsmay be varied, as shown in Figures 7 to 10. Additional variations may be made by making the heads on the shanks of, diiferent shape, such as square, hexagonal, etc., (not shown) but these shapes are not commonly used.

The operating members for the hot wire clamps are preferably provided with an enlarged cylindrical portion 35, and with a thrust bearing flange 35, carried by the enlargement 35 and comprising a substantially circular flange.

The thrust bearing flange 36 is preferably cut away and provided with a radial slot 31 on one side, as shown in Figure 5, for the purpose of permitting the assembly or separationof the operating member 20 from the hot wire clamp.

The hot wire clamp 38, shown in Figures 1 to 5, preferably include a fixed jaw member 39 and a movable jaw member 40. The fixed jaw member as may have its main body of substantially T-shape in cross-section, including a rearwardly projecting rib M carried by a flat body 42.

The rearwardly projecting rib 4! may carry a diagonally extending lug 43, which extends toasoa oee- 5 ward the cylindrical emaigement as, and hasan upper fiat thrust surface 44 engaging the lower surface 135 of the thrust flange 36.

Inits operation, opening or shuttin the hot wire clamp,- the-operator 2-0 is urged downwardly in Figure 1 by the movabie jaw and its Spring, and this movement is resisted by the' thrust surface "45 engaging the stop surface 44 on lug 43 over :a wide range of movement comprising substantially 270 degrees.

The slot 31, Figure 5, is, however, adapted to pass the lug 43 when the jaws are opened.- by some other means, such as a prying member or a tool of suitable thickness to hold the jaws open. Then the operating member 29 may be -rotated until the slot 37 registers with the 1ug'43, and the parts are position to remeve'or insert the operating member 20, v

Rotation of the operating member also pref,- erably' limited by providing the thrust flange 36 with a further radial extension '46, Figure 5, which engages the side of the rib- 4| atthe slot 41-, Figure 1, which extends into the rib 4'l Slflficintly to provide space for the rotation of the main part of the circular thrust flange 36.

The stop extension 46 prevents the user from rotating the operating member 20 so far that the cam might pass off the follower. In addition to the thrust flange 36, which extends at right-angles to the axis of the shank 2| or operator 20, the said shank carries -'a cam flange 48 above the thrust flange 36, and the cam flange 48 in this embodiment of the invention may be of uniform radial size, but the cam flange 48 changes its axial location gradually from the point 49 Figure 7, to 'the point 50, which may be at about 90 degrees from the point 39 in a-rotative direction.

The intervening art 5| of the cam may be called the rise of, the cam, and it is also shown in Figure 1 between the points 50 and 49. The remaining portion 52 of the cam has very little or no slope, andmay be called the dwell of the cam 43, as it is substantially at right angles to the axis of the shank 21,

At its beginning 49, the rise 5 'l of the cam is integrally attached to the thrust disc 36 adjacent the clearance slot 31. At its other end, that is, the end of the dwell '52, the'cam 48 is-formed with a stop surface 53 which is 'curv'edto fit against the adjacent side and stopsuriace -54 of an inwardly projecting lug 55, Figure 3, on 'the movable jaw, this lug also having end surfaces 56 which serve as a follower for the cam48,-and are=carried by the movable jaw-40 so that the cam may engage and move the movable jaw.

At its upper end, beyond the cam 48, the operating member 2!] is provided with a cylindrical shank extension 5! which serves as a shaft or trunnion, being rotatabl-y mountedin thetbearing bore 58 of an integral bearing formation 59., which forms a part of the fixed body 39 The shaft extension 5:! ofthe shank preferably has'a fiatend lie-for engagement-with:a-compression spring iii of helical form, the other end of which engages the base 62 'of the 'bore5'8. The purpose of the compression spring 61 is to :urge the operating member :20 axially in its bearing bore'EB to keep'the thrust fiange-36;with'its lower surface d5 engaging the top 44 f stop lug 43. This prevents rattling of the operator 'on'the clamp assembly'w'henthe clamp has been installed upon a conductor.

'Withoutthespr-ing :6 l the slight amount of-end play, which is produced by ordinaryrma'nufacturinc variatinns, permits the :o'rua'rator :20 to :be

6 slightly looseafter the tensionof the clamp'spring 63 is released by the line conductor between the clamping. .jaws.

The elimination of rattling is highly desirable because it might cause static disturbances that might interfere with radioreception, etc.

Referring to Figure '7 this is another form of operating member dine-rent from that of Figures 1 to 4, that it may be used with a hot wire clamp having a through bore at 58, or a bone at least of sufficient length to receive" the shank extension 63. In this case the operating member is intended to be removed when the clamp is ,in-- stalled on a transmission line conductor, and the end of the shank extension 64 is pointed or tapere'd slightly at fill for convenient reinsertion in the bore '53 when the hot wire clamp is again to be removed.

In order to permit the removal of this operat'or of Figure '7, its clearance slot 66 is so located that with the clamp in the closed position the slot '68 already registers with the lug 43, and the cam flange 38 is also recessed at 62! to clear the follower, such :as the follower 68 of Figure 6, at this time.

Thus there is only 'a slight difference between the removable operator of Figures :6 and '7 and the operator of Figures 1 to 4, which is intended to remain attached to thehot wire clamp. The removable operator clamp of Figure 6 has the advantage that only one operator need be provided for a multiplicity of clamps. This reduces the number of parts for the clamp by one and reduces their cost, and it prevents anyone who does not possess such an operator from tampering with the clampon the line.

The fixed jaw member 39 is preferably ,provided with an electrical connector at its lower end, and this may consist of an apertured extension 69,- Figure 4, which is provided with a through bore 10 for receivinga headed. vscrew bolt 'l-l. The extension E5 is formed .on its right side, in Figure 4, with an upper and lower V-shaped groove 12 13 above and. below the bore 10.

Above the grooved portion 12 the body extension 69 carries a transversely extending fiat stop flange 14, which is adapted to engag the end of the tap wire -15 to limit its insertion into the connector.

At the right end of the through bore T0 there and the screw-bolt l?! 'preferablyhasan elongated head '79. The elongated ihead 7'9 ,prie'fera'blylhas V-shaped grooves '80 on the side toward the tap wire 15' above and below the bore '18,, Figure 4.

The shank '81 of the screw bolt 1| 'is'threaded to receive anut 82,?Which engages a spring lock washer '83 and "reacts against a fiat surface 84 on the body extension 69. Thus a tap wit-e15 may be inserted in the hole 18 "of the bolt Tl from below until it hits the stop flange T4. A tightening of the bolt nut '82 will-cause the tap wire -15 to-be "clamped between the -'-V-shaped grooves -13 and '8ll,-giving four linecontacts betigveen the connector'and thecylindrical tapwire 1 The length of the contactds substantial-so that contact resistance is reduced toaniinimum. "The head We of the "screw bolt H is preferably convexly curved from top to bottom and provided with an outwardly projecting rib-' llpwhich projects above the s'topflangel4- and streamlines the entry into -th'e space between the jaws, as-shown' in Figure 4. Thus there is no chance of the conductor catching on the head of the bolt H or the stop flange 14 as the clamp is put on the line.

The movable jaw 49 is preferably formed at its lower end, Figure 1, with a diagonally extending guide nose 85, Figure 1, the lower surface 86 of which aids in guiding the line conductor into the space between the two clamping members. This guide nose 85 may be in the form of a halfring having a pair of forwardly extending side portions El and a transverse portion 88. The aperture in this half-ring serves the useful purpose of saving material and clearing the stop flange M.

The guide nose 85 is integrally supported upon a V-shaped clamping formation 89, which has a transversely extending V-shaped trough 90 on the side toward the fixed clamping member 39. The trough 99 is adapted to receive the line conductor and to clamp it against the relatively fiat opposed clamping surface 9I on the fixed clamping member 39.

This gives a three-line contact between the line conductor and the hot wire clamp. The transverse length of the clamping surface 9|, and the transverse length of the trough 90 is such that there is an extended contact area, reducing contact resistance. The contact 9| may be convexly curved from left to right. The body 69 may be provided with a partially cylindrical groove 34, Figure 4, for receiving the lower corner !35 of the trough member 89, thus permitting the clamp to close on smaller wires.

The fixed jaw member 39 preferably has a substantially rectangular body extending upwardly from the contact surface 9i, and this body may be provided with a rectangular aperture (09, Figure l, bordered at each side by an upwardly extending frame member IOI. The aperture I is for the purpose of passing the follower lug 55 so that it may come into engagement with the cam 48.

The aperture Hlil is also large enough so that the upper part or dwell 52, of the cam 48, may project through it, as shown in Figure 4. The frame members ltI are preferably provided on each side with forwardly projecting substantially triangular guide flanges, I92, I03, Figure 1, Figure 3.

These flanges on the fixed jaw 39 cooperate with the movable jaw 49 to prevent the line conductor from coming up into contact with the follower 55, since the flanges project into position to engage the line conductor when the jaws are open, as shown in Figure 4.

Above the aperture 599 the fixed jaw member 39 is provided with a transverse flat flange I94, joining the upwardly extending frame members I9! and supporting the diagonally extending bearing member 59. This bearing member comprises an integral tubular member, as previously described, with a bore 58 for receiving the shank portion of the operator 20.

The pins 99, Figure 22, comprise integral cylindrical members which project laterally from the flat flange H35 at each side, and are preferably of such length that they do not project beyond the guide flanges I92.

The purpose of the pins 98 is to hold the spring 63 in proper position, and the pins 98 are spaced from the fiange I04 by a slot I95 on each side for receiving parts of the spring 63.

On the side of the fixed jaw member 39, toward the operating member 20, the rectangular frame surrounding the aperture I0!) is substantially fiat, but it may be provided with projecting lugs I06 on each side (Figure 2) and laterally extending re-enforcing ribs Iill on each side of the body portion 69, these being spaced from each other to provide an upwardly extending groove I 98 on each side for receiving the free ends or legs I09, of the spring 63.

The side of the rectangular frame I64 is also preferably provided with a pair of guide lugs H0 above the aperture I99, Figure 2, for the purpose of strengthening the transversely extending frame member, which is grooved or cut away at III outwardly of the lugs H9 to provide a plane surface for engaging the spring legs I99.

The spring 63 may consist of a steel spring having a U-shaped portion H2, Figure 4, the yoke H3 of which engages the outside of the movable jaw member ill, Figure 4. From the U-shaped portion H2 the two legs of the spring extend backwardly, being bent at substantially right angles at H4 where they extend over the upper corners of the movable jaw 45 on each side of the upwardly extending ribs 96.

From the bend H4 the spring is formed with a plurality of helical turns, as indicated at H55, on each side and after turning about the pins 98 a plurality of times, such as, for example, three turns, the spring is provided with the downwardly extending radial legs W9.

It should be noted that the helical turns H5 of the spring 63 are preferably made considerably larger than the pins 98, in order to increase the resiliency of the spring and to increase its capability of returning to its original shape. Originally the legs H39 extend radially away from the helical turns I !5 of the spring at a point on the periphery which is forwardly of the U-shaped bend II 2, so that before tensioning the spring its legs I99 would stick off to the right of Figure 4.

After the spring has been placed upon the pins 98, and the movable jaw has been put in place with its bearing surfaces 9'! engaging round parts of the pin 98, then each leg of the spring may be bent outwardly of the guide flanges I02 and pried backwardly by means of a screw driver until it rests with its end in the groove I68, thus placing the necessary tension on the spring.

In some embodiments of the invention the spring may be held in place by grooves for the yoke H3 of the spring, or the projecting pins 93 may be eliminated, but the projecting pins eliminate any possibility of the spring sliding upward off the two clamping members.

The operating member 29 is preferably inserted with its shank 51 in the bearing member 59, the slot 31 passing the lug 63. This should be done before the legs of the spring are tensioned, since the jaws may be separated sufficiently when there is no spring tension to insert the operator. The jaws must be separated to insert the operator because the end stop surface 53, Figure 3, on the dwell of the cam, engages the side stop surface 54 on the follower 55 when the jaws are closed for preventing the operating member 29 from being removed from the clamp in the embodiment of Figures 1 to 5.

The operation of this tap clamp is as follows: The operating member 29 may be rotated counterclockwise while holding the fixed jaw against rotation in order to open the jaws. This may be accomplished manually with a handle such as Figure 8, by means of an operator permanently attached to a pole 29, as shown in Figure 9, bymeans of a Universa pole, as shown in Figure,

10, or by a clamp stick engaging the ring 22 of Figure '7.

The spring parts H2 and I59 urge the jaws tightly together, pivoting about an axis which is substantially the axis of the pins 93. As the operator is rotated counterclockwise the rise 5| of the cam 48 engages the follower 55 at the left follower surface 56 and slides against this follower, while pressing the follower in such a direction that the follower recedes in aperture HIE, while the movable jaw 46 is pivoted away from the fixed jaw.

The camming action of the rise of the cam against the follower tends to urge the operating member 25 downward but this is resisted by the thrust flange 36, "the bottom surface 45 of which slides upon the top 44 of lug 43.

This pivotal movement continues as long as the cam rise 5| is engaging the follower, until the jaws are open to the position of Figure 4, after which continued rotation of the operating member 25 causes the dwell .52 of the cam 48 to engage the follower 55; and at this time the follower has receded until it out of the aperture H19 and the cam flange G8 is projecting through the aperture lhlhas shown in Figure 4.

As the rotation continues the dwell .52 of the cam 48 engages both .end surfaces 56 .of the follower 55, and since-there is no longer any slope engaging the follower there is no tendency for the jaws .to react against the cam in such way as to close the jaws. In-other words, the dwell of the cam holds the jaws open, and :on account of friction between the follower and the cam the parts are firmly held in open position.

The limit of the rotationof the cam is reached when the stop lug 45 has its leadingsurface H6 engaging the lug 43, beyond the base of the slot 41, as shown in Figure -5 in dotted lines. Thus the stop member 46 prevents the operator from being rotated so far that the follower would pass off the end .53 :of the cam.

Assuming that the clamp is to be applied to an energized transmission .line, .a tap wire such as a ground wire should first be placed in the connector bolt H and secured by tightening the nut 82. Theother .endof the wire may be grounded, the jaws may be opened as described and the ring v22 may be engaged .by the jaws H1, H8 of the clampstick .119.

The clamp stick H9 preferably has .a tubular metal head 12D, whichis provided with a slotted apertureat the-upper .endIfor passing the ring 22. Inside the tubular head of the clamp stick there is a rotatable sleeve 122 which also has a slot I23, adapted to'register with the slot '12] in one rotative position, and adapted to extend transversely to the slot I21 when the sleeve I22 is turned '90 degrees in the tubular metal head [26.

This rotative motion of the sleeve 1.22 may be accomplished by providing a slot 1 24 in "the .head I20, and by having a screw bolt I25 which projectsifrom the slot and is carried by the sleeve 122. The clamp stick head 120, also preferably has upwardly extending flanges "I26 on each side of the end of the head, separated by a slot at I21 for receiving the lug 43 'on the fixed jaw.

While the aperture I 21 "has been described as a slot, it preferably has a rounded portion 128 midway between its ends for receiving the enlargement 3'5 onthe opera-ting member 29. The purpose of the slots l2! which receive the'lug '43 of the fixed jaw is as follows:

Tap wires 15 may doe relatively heavy and stiff, V

,. by passage of time, rattling or the like.

Then the clamp stick can be withdrawn sufll ciently so that the lug '43 is out of the slot 12.! and the clamp stick engages only the ring 2.2 of the operating member 20.

This ring, however, is retained in the clamp stick head I20 because of the inner sleeve 122, which has been turned until its slotted aperture il25 extends transversely to the slotted aperture The inside of the tubular head i2!) is provided with a rounded concavity 129, into which the ring 22 may be pulled, but as the ring is transverse to the elongated slot aperture 'I2l. :it cannot come out. Then the lineman may rotate the clamp stick in a clockwise direction, rotating the operating member 20 and causing the'cam 48 to turn in such manner that the dwell passes out from under the follower and the follower eventually passes down the rise of the cam while the jaws are closed by the spring.

The line wire is then clamped by the jaws under the influence of the spring, and this gives .a uniform and lasting contact between the line wire and the clamp which can never be loosened The spring pressure is taken by the jaws against the line wire and the cam is relieved of load, but the spring 6| in bearing member 59 constantly urges the operating member 20 axially with its thrust flange 35 against thrust lug 43, so that there can be not rattling of the operating memberon the :line.

The friction of the flange 36 against stop member 43 is such that the cam does .not tend to rotate either. Referring now to Figure 6, this .figure discloses an operator 20a of slightly difierent form. It has the same ring 22 and shank .2], thrust flange 36 and cam 48, but the shank extension 5'Ia above the cam is preferably longer and provided with a slightly tapered portion "51b. The reason for this is that the operator 20a is intended to be removed after the clamp is placed on the line, and re-inserted when the clamp is to be removed from the line.

Thus the tapered portion 5'lbis easier to insert into the bore 58 than it would be if it did'not have such a tapered portion. Also the bore 58 fin'the "bearing member 59 Ba through bore, permitting the use of a longer shank portion 51a, 57b.

In the clamp of Figures 1 to 5, 'the clearance slot 31 for passing the lug 43 is also so located that the-operating member 20 cannotberemoved from the assembly until the jaws are wide open and actually opened to a position beyond that shown in Figure 4. That-position is most easily attained by first removing the spring, andthereason for this is that the operator 20,'of Figures 1 to 5, is not intended to be removed-from the clamp assembly except when one is trying to disassemble the device. 7

In thedeviceof Figure 6, the clearanceslot 51a is located, as shown in Figure 11, so that it registers with the lug '43 when the jaws'are "closed. When the jaws have been opened and the-spring strain is taken by a line conductor between the jaws, then the cam 48 of operator-20a is relieved 11 of its strain and it may be turned back to the original position of the operator 20a, where the slot 310. registers with lug 43, and the operator 20a may be removed by merely pulling downward.

Thus the operator 26a may be removed after the clamp of Figure 6 has been placed on the line, and this clamp has the advantage that it will be cheaper because it is not necessary to provide an operator for every clamp. One or two operators may serve the purpose of applying and removing a great many clamps, and the operator becomes a tool that is carried in the tool box and used when it is necessary to apply *or remove a clamp.

Such clamps are cheaper because they have the advantage that they cannot be removed except by one who has a suitable operating member 20a. Such an operating member 20a may also have'its lower end provided with the handle ure 1. In such case provision is preferably made on the operating member 20a for permitting the clamp stick head to twist the tap wire.

Such a provision may be made on the operating member 20a, providing an enlargement I36 above the shank portion 2| and below the thrust flange 36, Figure 6. This enlargement I 30 has a pair of laterally projecting ribs l3l, which are integrally attached to the shank 2| and to a radially projecting rib I32.

The ribs I31 serve to engage in the slots I21 of the clamp stick head when the ring 22 is drawn into the clamp stick head. The elongated stop flange I33, above the ribs I31, engages the top of the clamp stick and prevents the eye from being drawn into the clamp stick any farther.

The construction of the clamp stick, which may be like any of those of the prior art of this type, is such that under these conditions the operating member 20 is rigidly secured in the end of the clamp stick. Such rigid securement is essential since the tapered end 511) of the operator 20a must be pointed toward the bore 58 of bearing 59 to insert the operator.

Aside from the fact that the operator of Figure 6 is removable, the device of Figure 6 cperates in every way substantially like that of Figures 1 to 5.

It will thus be observed that I have invented an improved hot wire clamp which provides a constant resilient engagement with the line wire, and which can be applied or removed by means of an operator having a cam for camming the two jaws apart against the pressure of a spring.

7 There is no danger of the present clamp losing its characteristics due to corrosion, as the existence of a slight amount of corrosion on the cam will not prevent it from performing its func- 12 by vibration, nor does the clamp place undesirable strains on the line conductor in the course of its application or removal.

The present clamp may be embodied in a form which permits the removal of the operating member, thus reducing the number of parts of the clamp, since one operating member may be used for many clamps. This also reduces the cost of the device and reduces the weight on the line, and prevents anyone from tampering with the clamp on the line who does not have an operating member particularly adapted to be used with the clamp.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not Wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a hot wire clamp, the combination of a fixed jaw member and a movable jaw member, said jaw members having pivotal engagement with each other at one end, and being provided with clamping surfaces for engaging a, line wire at a point spaced from said point of pivotal engagement, connector means carried by one of said jaws for engagement with a. tap wire, and an operating member comprising a shaft rotatably mounted in a bearing in the fixed jaw member and having a cam engaging an integral follower carried by the movable jaw member, the said cam having a helical portion with a rise that acts in an axial direction, and said cam moving said movable jaw member from the closed to the open position upon rotation of said shaft, and resilient means for urging the jaws into closed position, said operating member being provided with a radially projecting flange below said cam, and said fixed jaw member having a stop lug located below said flange, the flange of said operating member reacting against said lug when the cam acts on the follower.

2. In a hot wire clamp, the combination of a fixed jaw member and a movable jaw member, said jaw members having pivotal engagement with each other at one end, and being provided with clamping surfaces for engaging a line wire at a point spaced from said point of pivotal engagement, connector means carried by one of said jaws for engagement with a tap wire, and an operating member comprising a shaft rotatably mounted in a bearing in the fixed jaw member and having a cam engaging an integral follower carried by the movable jaw member, the said cam having a helical portion with a rise that acts in an axial direction, and said cam moving said movable jaw member from the closed to the open position upon rotation of said shaft, and resilient means for urging the jaws into closed position, said operating member being provided with a radially projecting flange below said cam, and said fixed jaw member having a stop lug located below said flange, the flange of said operating member reacting against said lug when the cam acts on the follower, the said flange being provided with a radial slot for passing said lug when the operating member is in a predetermined rotative position.

3. In a, hot wire clamp, the combination of a fixed jaw member comprising a metal member formed with a downward extension carrying a connector fora tap wire-said fixed jaw having an upwardly extending frame surrounding an aperture for passing afollower, said frame supporting a diagonally extending bearing member and having pivot surfaces on opposite sides of said bearing member, a movable jaw'member provided at its upper end with-concave bearing surfaces for engaging said first-mentioned pivot surfaces to pivot the movable "jaw on the fixed jaw, the said jaws being provided with-opposed wire clamping surfaces, spring mean having coiled portions adjacent said pivot surfaces and having radially projecting legs engaging outside the movable jaw and outside the fixed jaw to'urge them together, said movable jaw having a follower projecting through said aperture and an operating member having a shaft in said diagonal bearing and .having a cam for engaging said follower, said cam urging said movable jaw to open position upon rotation of the operating member, the said cam comprising a peripherally extending flange carried by the operator shaft, and having a substantially helical portion serving as a rise of the cam.

4. In a hot wire clamp, the combination of a fixed jaw member comprising a metal member formed with a downward extension carrying a connector for a tap'wire, said fixed jaw having an upwardly extending frame surrounding an aperture for passing a follower, said frame supporting a diagonally extending bearing member and having pivot surfaces on opposite sides of said bearing member, a movable jaw member provided at its upper end with concave bearing surfaces for engaging said first-mentioned pivot surface to pivot the movable jaw on the fixed jaw, the said jaws being provided with opposed wire clamping surfaces, spring means having coiled portions adjacent said pivot surfaces and having radially projecting legs engaging outside the movable jaw and outside the fixed jaw to urge them together,

said movable jaw having a follower projecting through said aperture and an operating member having a shaft in said diagonal bearing and having a cam for engaging said follower, said cam urging said movable jaw to open position upon rotation of the operating member, the said cam comprising a peripherally extending flange carried by the operator shaft, and having a substantially helical portion serving as a rise of the cam, the said cam also having a substantially flat portion serving as a dwell to hold the jaws open.

5. In a hot wire clamp, the combination of a fixed jaw member comprising a metal member formed with a downward extension carrying a connector for a tap wire, said fixed jaw having an upwardly extending frame surrounding an aperture for passing a follower, said frame supporting a diagonally extending bearing member and having pivot surfaces on opposite sides of said bearing member, a movable jaw member provided at its upper end with concave bearing surfaces for engaging said first-mentioned pivot surfaces to pivot the movable jaw on the fixed the said jaws being provided with opposed wire clamping surfaces, spring means having coiled portion adjacent said rpivot surfaces and having radially projecting legs engaging outside the movable jaw and outside the fixed jaw to urge them together, said movable jaw having a follower projecting through said aperture and an operating member having a shaft in said diagonal bearing and having a cam for engaging said follower, said cam urging said movable jaw to open position upon rotation of the operating member, the said cam comprising a peripherally extending flange carried by the operator shaft,

and having asubstantially helical portion serving as ariseof the'cam, the saidcam also having a substantially flat'portionserving as a dwell to hold the jawsopen, the said operating member being provided below said cam with a thrust flange, and said fixed jaw member having a lug engaging below said thrust flange for reaction of the thrust flange against said lug when the cam is'acting, said thrust flange and lug also serving to hold the operator and jaws in assembly, and said thrust flange having a radial slot located to pass said lugwhen the operating member is in a predetermined rotative position, the said slot being so located that it may be registered with said lug when the jaws are closed on themselves or upon a line wire.

-6. In a hot wire clamp, the combination of a fixed jaw member comprising a metal member formed with a downward extension carrying a connector fora tap wire, said fixed jaw having an upwardly extending frame surrounding an aperture for passing a follower, said frame supporting a diagonally extendingbearing member and having pivot surfacesonopposite sides of said bearing member, a movable jaw member provided at its upper end with concave bearing surfaces for engaging said first-mentioned pivot surfaces to pivot the movable jaw on the fixed jaw, the said jaws being provided with opposed wire clamping surfacea'spring means having coiled portions adjacent said pivot surfaces and having radially projecting legs-engaging outside the movable jaw and outside the 'flxed jaw to urge them together, said movable jaw having a follower projecting through. said aperture and an operating member having shaft in said diagonal bearing and having 'a cam for engaging said follower, said cam urging said movable jaw to open position upon rotation of the-operating member, the said cam comprising a peripherally "extending flange carried i-by the operator shaft, and having a sub-,

'stantially helical portion serving as a rise of the cam, the said cam also having a substantially flat portion serving a a dwell to hold the jaws open, the said operating member being provided below said cam with a thrust flange, and said fixed jaw member having a lug engaging below said thrust flange for reaction of the thrust flange against said lug when the cam is acting, said thrust flange and lug also serving to hold the operator and jaws in assembly, and said thrust flange having a radial slot located to pass said lug when the operating member is in a predetermined rotative position, the said slot being so located that it comes into registry with said lug only when the jaws are wide open beyond the maximum travel of the jaws when actuated by the cam.

7. In a hot wire clamp, the combination of a fixed jaw member and a movable jaw member, said jaw members having pivotal engagement with each other at one end, and being provided with clamping surfaces for engaging a line wire at a point spaced from said point of pivotal engagement, connector means carried by one of said jaws for engagement with a tap wire, an integral bearing carried by the fixed jaw member at its upper end and having its axis extending transversely to the movable jaw member, an integral follower carried by the movable jaw member, and an operating member comprising a shaft having a shank at its upper end'rotatably mounted in said 7 bearing in the fixed jaw member, said shank carrying an integral helical cam flange, the side of,

said cam flange engaging said follower, and the rotation of said operating member causing said cam to move said movable jaw member from the closed to the open position, said fixed jaw having a thrust lug extending toward said shank, and said operating member having a, radially extending thrust flange engaging the upper side of said thrust lug so that the operating member may react against the thrust lug at said radial flange when the helical cam flange acts on the movable jaw member, said thrust flange having a radial slot for passing said thrust lug, said slot being located to pass said lug when the jaws are opened to maximum position so that the operating member cannot be removed when the clamp is on the line.

8. An operating member for clamp connectors, comprising n elongated cylindrical shank, said shank being provided with an integral radially projecting cam member having a helical flange serving as a riser for engaging a follower upon a movable clamping member, the said shank extending outwardly from said cam and having a pointed cylindrical portion for insertion into a cylindrical bearing in the fixed clamping member of a tap clamp, the said operating member having on its shank below said cam an integral radially extending thrust flange for engaging a thrust lug on a fixed clamping member, and being provided at its lower end with a head for attachment to an insulating operating pole.

9. An operating member for clamp connectors, comprising an elongated cylindrical shank, said shank being provided with an integral radially projecting cam member having a helical flange serving as a riser for engaging a follower upon a movable clamping member, the said shank exprovided at its lower end with a head for attachment to an insulating operating pole, said thrust flange being provided at one side with a radial slot for passing said thrust lug, to permit the removal of the operating member when it is rotated with its slot in registry with the thrust lug.

10. An operating member for clamp connectors, comprising an elongated cylindrical shank, said shank being provided with an integral radially projecting cam member having a, helical flange serving as a riser for engaging a, follower upon a movable clamping member, the said shank extending outwardly from said cam and having a pointed cylindrical portion for insertion into a cylindrical bearing in the fixed clamping member of a, tap clamp, the said operating member having on its shank below said cam an integral radially extending thrust flange for engaging a thrust lug on a fixed clamping member, and being provided at its lower end with a head for attachment to an insulating operating pole, the said head comprising an integral ring formation of a size adapted to be engaged by a standard clamp stick, the said shank also having between the ring and the thrust flange an integral enlargement formed with a depending radially projecting rib for engagement in the upper slot in a clamp stick.

HENRY W. BODENDIECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,194,628 Hist Aug. 15, 1916 1,488,347 Johnson Mar. 25, 1924 1,515,666 Elderkin' Nov. 18, 1924 1,547,314 Frankel July 28, 1925 1,648,326 Sawyer Nov. 8, 1927 2,194,411 Tipsord Mar. 19, 1940 2,423,660 Reynolds July 8, 1947 

